Ellipsograph compass



March 1, 1932. w. G. BENNETT ELLIPSOGRAPH COMPASS Filed Sept. 12, 1929 W6. Ben I: e a:

INVENTOR.

A TTORNEY. f

Patented Mar. It, 1932 tanner wnnno e. Bi nnnjrn'orsoarroosn, onneoneantime oonirnss Application filed September 12,1929. Serial No.392,166.

The present inventionis directed to. improvements in compasses. r Theprimaryobjectof the invention is to provide an instrument of thischaracter so constructed that ellipses of various sizes can bequicklyand accurately drawn. I 7

Another object of the invention is to provide an instrument of this kindso constructed that circles may be described, the instrument beingcapable of being adjusted for forming ellipses.

A further object of the invention is to provide an instrument ofthis'nature so con-v structed that a complete ellipse may be drawn uponimparting to the instrument a completerotation or twist.

With these and other objects in view,'th1s invention resides in thenovel features ofconstruction, formation, combination and arrangement ofparts to be hereinafter more fully described, claimed and illustrated inthe accompanying drawings, in which:

Figure 1 is a perspective view of the device. Figure 2 is an enlargeddetail sectlonal View through the casing.

Figure 3 is a sectional view on the'line 33 of Figure 1.

Referring to the drawings, 1 designates the leg of the devicewhich'consists of alined upper and lower sections 2 and '3,respectively, the opposed ends of which are spaced.

and are provided, respectively, with lateral arms 1 and 5. A pair ofupper and lower links 6 and? are employed and have their inner endssecured to the ends of the arms 4 and 5 by screws 8 which serve to holdthe arms and links engaged with sufficient frictic-n to preventaccidental movement but permit relative adjustment when desired. 7

Pivotally mounted between the outer ends of the links 6 a transverseopening 10 formed therein and into which extends a set screw 11 which isadapted to engage the rod 12 slidable in the opening 10, said rod beingconnected with the leg 13. The upper end of the leg 13 has pivotallyconnected thereto, as at 14, 21 connector 15, which consists oftelescopically connected sections 16 and 17, there being a coil spring18 interposed between the upper and 7 is a cylinder 9 having end oi thesection tiller 19 nou1ited ingthe upper end of the section 17, thelatter telescopic connection. I I 7 Ti e filler 19 is pivotallyconnected, as at being of hollow formationto allow torithe 20, tothejbar 21 fixed to-the head 22, said headfharing a'knurled' knob23carried thereby facilitate rotation.

The head 22is alined with .thesection 2 of the leg 1 and has fixedthereto abeveledggear 24-. A sim'i'largear 25-.is fixed to, the upperend ofthe section-20f said leg. A casing 26 is. provided which consistsof separable com- I pleinentary sections 27 adapted to. engage in thegrooves 28 and 29 formed, respectively,

of the casing are held together bybolts 30.

Extendingint o the casing is a shaft 31 which is journaled in thebearings-32 pro vided in the casing. v Loosely mountedon the in the head22 and section 2. .Thesections 27 shaft are-beveled: pinions v33 which.mesh

with the gears 24 and 25, as clearly shown in Figure. 2 of the drawings.The shaft is provided with an arm 34in order that the shaft can be held.against rotation'with one hand while the other hand is employed forrotating the head 22-"througl1 the medium of the knob;

."The: action 3 of the'leg 1 is ained with a steeLpoint35 while the'leg13 carries the head'36 :inwhich is mounted a lead point 37.:

- H The spring 18 will tend to urge the section 16 downwardly, thusholding the lead point 37in contact with thepaper.

When it is desired to form an ellipse, the links 6 and 7 are adjustedfortheproper size, whereupon the knob 34 is held firmly inone hand'whilethe knob 23 istwirledwith the other hand and owing to the differentialaction of the 33, an ellipse-can be easily and accurately formed j c Ofcourse, when it isdesired to merely drawa circle, the knob 23 isturnedsynchronously withthe shaft 31.

In drawing an ellipse, it' will be noted that the leg 1 will rotate inonedirection while the connector 15 and leg 13 will rotate in areversedirection, this being, of course, dueto gears 24 and 25 and thepinions the presence of the intermeshing gears 2 and 25 and pinions 33.

From the foregoing, it is thought that the operation and many advantagesof the herein described invention'will be apparent to those skilled inthe art without further description, and it will be understood thatrious changes in the size, shape, proportions, and minor details ofconstruction may be resorted to without departing from the spirit orsacrificing any of the advantages of the invention.

What is claimed is:

1. A compass of the class described comprising a main leg consisting ofupper and lower sections, a head, a connector pivotally connected-withthe head, a second leg pivotally connected with the connector, linksconnected with the upper and lower sections of the main leg, a rodcarriedby the second leg and adjustably connected with the links, and agear assembly between the head and main leg sections to rotate the mainleg and second leg in reverse directions.

2. A compass of the class described comprising a main leg consisting ofupper and lower sections, a head, gears fixed to the opposed ends of thehead and upper section of the leg, a shaf-textending between the gears,pinions loose upon the shaft and meshing with the gears, a second leg, aconnector between the second leg and head, arms carried by the opposedends of the upper and lower sections of the main leg, links connectedwith the arms, a rod projecting from said second leg, and means foradjustably connecting the rod with the links. H

3. A compass of the class described comprising a main leg consisting ofupper and lower sections having arms carried by their opposed ends, ahead alined with the main leg sections, a second leg pivotally connectedwith the head, means for adjustably connecting the second leg with thearms, a differentiel gear-assembly etween the head and'main legoperating to rotate the main leg and second leg in reverse directions.

e. A compass comprising a main leg formed of a pair of alined sections,a second leg, a head, a differential gearing between the head and one ofthe sections of the main leg, connecting means between the second legand the head, and connecting means between said s cend leg s pai of. alne e tines 02E he ma n leg- 5,. A compass comprising a main leg formedor" a pair of alined sections, a second leg, a head, a difierentialgearingbetween he h ad nd n f the sec ions of th mai leg, moanspivotally connecting the second leg with the head, and a yieldableconnection between said second leg and said pair of alined sections ofthe main leg.

6. A compass comprising a main leg formed of apair of alined sections, ahead,

nee-ace? a casing forming connecting means between the head and one ofthe sections of the leg, a shaft passing between the head and saidsection of the leg and mounted in the casing and projecting to form ahandle, a differential gearing between said section of the leg, saidhead and said shaft, asecond leg, means pivotally connecting the secondleg with said head, and a yieldable connection between said second legand said alined sections of the main leg.

In testimony whereof I afiix my signature.

WALDO G. BENNETT. 1 3.

